Controlled fluid transport in microfabricated polymeric substrates

Abstract

Microfluidic devices are provided for the performance of chemical and biochemical analyses, syntheses and detection. The devices of the invention combine precise fluidic control systems with microfabricated polymeric substrates to provide accurate, low cost miniaturized analytical devices that have broad applications in the fields of chemistry, biochemistry, biotechnology, molecular biology and numerous other fields.

We claim:  
     
       1. A microfluidic device, comprising: 
       a body comprising a substantially polymeric substrate layer and a cover layer, the substantially polymeric substrate layer comprising at least two intersecting microchannels embossed therein, the cover disposed over at least a portion of the at least two intersecting microchannels.  
     
     
       2. The microfluidic device of claim  1 , wherein the cover layer is laminated to the substantially polymeric substrate layer. 
     
     
       3. The microfluidic device of claim  2 , wherein the cover layer and the substantially polymeric substrate layer are fused. 
     
     
       4. The microfluidic device of claim  1 , wherein the cover layer is laminated to the substantially polymeric substrate layer by one or more of adhesive bonding, sonic welding, pressure bonding, thermal bonding and thermal bonding under pressure. 
     
     
       5. The microfluidic device of claim  1 , wherein the cover layer is substantially fabricated from glass, or a polymer, or a combination thereof. 
     
     
       6. The microfluidic device of claim  1 , wherein the microchannels are embossed as grooves in a substantially planar portion of the substantially polymeric substrate layer, which cover layer overlays the grooves, thereby forming a closed microchannel. 
     
     
       7. The microfluidic device of claim  1 , wherein the channels have a surface potential associated therewith. 
     
     
       8. The microfluidic device of claim  1 , wherein the at least two channels support electroosmotic flow of fluidic material in the channels. 
     
     
       9. The microfluidic device of claim  1 , wherein the at least two channels have a zeta potential associated therewith which supports an electroosmotic flow of at least about 5×10 −4  cm −2 v −1 s −1  for a 5 mM sodium borate buffer at pH 7 when said buffer is disposed within the channels. 
     
     
       10. The microfluidic device of claim  1 , wherein the at least two channels have a zeta potential associated therewith which supports an electroosmotic flow of at least about 1×10 −5  cm −2 v −1 s −1  for a 5 mM sodium borate buffer at pH 7 when said buffer is disposed within the channels. 
     
     
       11. The microfluidic device of claim  1 , wherein the at least two channels have a zeta potential associated therewith which supports an electroosmotic flow of at least about 1×10 −5  cm −2 v −1 s −1  for a sodium borate buffer between about 1 and about 100 mM at a pH of about 6 to about 9 when said buffer is disposed within the channels. 
     
     
       12. The microfluidic device of claim  1 , wherein the at least two channels have a zeta potential associated therewith which supports an electroosmotic flow of at least about 2×10 −5  cm −2 v −1 s −1  for a sodium borate buffer between about 1 and about 100 mM at a pH of about 6 to about 9 when said buffer is disposed within the channels. 
     
     
       13. The microfluidic device of claim  1 , wherein the at least two channels have a zeta potential associated therewith which supports an electroosmotic flow of at least about 1×10 −4  cm −2 v −1 s −1  for a sodium borate buffer between about 1 and about 100 mM at a pH of about 6 to about 9 when said buffer is disposed within the channels. 
     
     
       14. The microfluidic device of claim  1 , wherein at least one of the at least two microchannels comprises at least one cross-sectional dimension in the range of from about 0.1 micron to about 500 microns. 
     
     
       15. The microfluidic device of claim  1 , the device further comprising a plurality of ports proximal to the channels, the ports each optionally comprising one or more electrode disposed therein. 
     
     
       16. The microfluidic device of claim  15 , comprising at least four ports, each proximal to a terminal region of at least one of the at least two microchannels, each port optionally comprising at least one electrode disposed therein. 
     
     
       17. The microfluidic device of claim  16 , the device comprising at least four electrodes, with at least one electrode being disposed in each of the at least four ports, the device further comprising an electrical controller for concomitantly applying an electrical potential to each of the four electrodes. 
     
     
       18. The device of claim  17 , wherein the electrical controller comprises a voltage controller. 
     
     
       19. The device of claim  18 , further comprising a computer operably linked to the voltage controller, wherein the computer is programmed to regulate electrical potential of the electrodes. 
     
     
       20. The microfluidic device of claim  1 , further comprising fluid disposed within the at least one microchannel. 
     
     
       21. The microfluidic device of claim  1 , the substantially polymeric substrate comprising at least 60% polymer. 
     
     
       22. The microfluidic device of claim  1 , wherein the substantially polymeric substrate layer is fabricated from a material which is selected from: a rigid material, a semi-rigid material, an opaque material, a semi-opaque material, and a transparent material. 
     
     
       23. The microfluidic device of claim  1 , wherein the substantially polymeric substrate layer comprises one or more of: a polydimethylsiloxane (PDMS), polymethylmethacrylate (PMMA), polyurethane, polyvinylchloride (PVA), polystyrene, polysulfone, and polycarbonate. 
     
     
       24. The microfluidic device of claim  1 , wherein the cover layer comprises a quartz window. 
     
     
       25. The device of claim  1 , wherein the cover layer and the substantially polymeric substrate layer are substantially planar. 
     
     
       26. The device of claim  1 , the device further comprising a surface coating on the substantially polymeric substrate or on the cover layer, which coating, when present, modifies the zeta potential of the polymeric substrate, or the cover layer, thereby modifying the zeta potential in at least one of the at least two microchannels. 
     
     
       27. A device for fabrication of a polymeric substrate, the device comprising: a mold for embossing the surface of a substantially polymeric substrate with a microchannel network, the mold comprising an embossing surface comprising a network of intersecting raised or lowered regions for embossing at least two intersecting grooves in the polymeric substrate, wherein the intersecting grooves embossed in the substantially polymeric substrate by the embossing surface have at least one dimension between about 0.1 and about 500 microns. 
     
     
       28. The device of claim  27 , wherein the embossing surface is a stamp, or, a rolling press. 
     
     
       29. The device of claim  27 , further comprising a polymeric substrate in contact with the mold. 
     
     
       30. The device of claim  29 , wherein the polymeric substrate is a region of a polymer sheet. 
     
     
       31. The device of claim  27 , the embossing surface further comprising an additional raised or lowered region corresponding to a well, groove, chamber, reservoir or additional channel region.